As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ACFT HAD A LT PACK DEFERRED. PILOT REPORTED THE RT PACK OVER PRESSURIZED ON TAKEOFF. 10TH STAGE VLV CLOSED & CREW WAS NOT ABLE TO RE-OPEN THE VLV. THE RT PACK SHUTOFF & THE AIRPLANE DEPRESSURIZED, PAX O2 MASKS WERE DROPPED & USED. THE ACFT DIVERTED, PN 117025-02 & 117025-03. SEE ALSO SDR 2012010701130 201128487.